Low-income women in the US have the highest rates of overweight and obesity, putting them at increased risk for diabetes, heart disease, and other chronic illnesses. Because mean BMI gradually increases during adult life and peaks at 50-59 years of age, low income women between 40-64 years are a group deserving of special attention. While there is sufficient evidence that some behavioral weight management interventions are effective in producing clinically meaningful levels of weight loss with reductions in cardiovascular risk factors and delayed onset of diabetes, there is a research gap in translating these efficacious interventions to real life settings and diverse population groups. Research that seeks to translate effective behavioral weight management interventions from resource-intensive efficacy trials to long-term adoption and implementation by public health settings serving a diverse low-income population is timely and of great public health significance. This translational research can provide important information to decision-makers about evidence-based intervention delivery, resource allocation, and workforce preparation. The overall goal of the proposed research is to evaluate the processes and outcomes of translating from research to practice an intense, evidence-based behavioral weight loss intervention with demonstrated effectiveness among midlife low-income women. Originally studied in a single coordinated community health care center/church setting and delivered by research staff, we will evaluate the translation of and test the effectiveness of this intervention as implemented by existing staff in a range of county health departments supported by local community resources. To evaluate the translation process, we will use the RE-AIM framework, diffusion of innovation theory, and systematic models of adaptation to assess: 1) factors related to reach;contextual or setting-specific factors necessary for successful adoption and implementation;2) effectiveness of facilitator training and stakeholder collaborations;3) adaptation and fidelity during implementation;and 4) costs associated with the implementation and outcomes. To test the intervention's effectiveness, we will enroll 240 overweight or obese low-income women, 40-64 years of age, at 6 representative public health agencies. Participants will be randomized to receive a 16-week behavioral weight loss intervention or usual care (wait listed control group). The primary study outcome at 5 month follow-up is weight change;secondary outcomes include change in blood pressure, dietary intake, physical activity, and quality of life measures. After 5-month follow-up, the wait listed control group will receive a 10-week intervention, refined by lessons learned during the 16-week implementation. For this group, we will conduct a second round of process and outcome evaluations. Also, for both groups, we will evaluate maintenance of weight loss 6 months post intervention.